The current study aims to tackle one of the main obstacles in the application of anaerobic ammonium oxidation (Anammox) technology, i.e., the extreme slow growth of the Anammox bacteria. Three conventional sludge has been tested in sequencing batch reactor for Anammox enrichment, including conventional aerobic sludge, denitrification sludge, and anaerobic sludge. With a high selection stress and insufficient oxygen control, the reactor seeded with aerobic sludge reached 50–60% total nitrogen removal after 240 days whereas that seeded with anaerobic sludge failed to establish Anammox activity. Anammox process was successfully established in the reactor seeded with denitrification sludge with a total nitrogen removal of approximately 80% after 150 days under strict oxygen control (DO <0.2 mg/L) and low selection stress. Under the same operational condition, the reactor seeded with anaerobic sludge reached only 20–30% total nitrogen removal. All the reactors experienced fluctuating performances during the enrichment process, which was believed to be the consequence of inhibitory factors such as dissolved oxygen, nitrite and free ammonia as well as undesirable coexisting bacteria which compete for the same substrate. The denaturing gradient gel electrophoresis (DGGE) band from the amplified DNA samples extracted from different enrichment stage showed a clear evolution of the microbial composition as reflected by the change in the band locations and their intensity.

The occurrence of endocrine-disrupting chemicals (EDCs) in the aquatic environment has brought increasing concern due to their potential adverse impacts on ecosystems and humans. These compounds are generally present in complex water matrices, such as surface waters at trace levels (ng L⁻¹) making their analysis difficult. In this work, an analytical method for the simultaneous determination of 13 EDCs, including 5 steroid estrogens, 1 progestogen, 1 androgen, and 6 endocrine-disrupting phenols in water, was developed using solid phase extraction (SPE), derivatization, and gas chromatography-mass spectrometry (GC-MS). The method was validated by spiking the 13 EDCs to the interest matrix. The recovery was in the range of 52–71% with an average of 62%. The limits of quantification were 1 and 5–10 ng L⁻¹ for phenolic compounds and hormones, respectively. The validated method was applied to assess the contamination level of the targeted EDCs in 15 sites collected from six rivers located at the cross-border area of Northern France and Belgium. The majority of the considered compounds were detected in the sampling sites and among them, bisphenol A (BPA) was found at the highest level which can be up to 286 ng L⁻¹. However, NP was the most frequently detected, followed by BPA and PG.

Bisphenol A (BPA), a well-known endocrine-disrupting chemical, is receiving increasing concerns regarding its adverse effects on the endocrine system in wildlife and humans. This study was designed to investigate BPA pollution in environmental media in plastics industry areas and to explore the relationship between BPA pollution and the characteristic of different plastics industry. A total of 66 river water samples, 6 aquatic animal samples, and 64 surface soil samples were collected from three cities with different characteristics of plastics industry in southeast China. BPA concentrations in river water (240–5680 ng L⁻¹), aquatic animals (116.13–477.42 ng g⁻¹), and surface soil (38.70–2960.86 ng g⁻¹) were highest in Yuyao City where the plastics industry mainly involved in the production of plastic raw materials. BPA concentrations in Taizhou City were modest and comparable to those reported elsewhere though Taizhou is characterized by its massive production of plastic products. BPA concentrations in Wenzhou City were the lowest where relatively low activities are involved in the plastics industry. Our data indicate that the plastics industry involved the use of BPA as an intermediate in production of raw plastics such as polycarbonate plastics and epoxy resins was the dominant cause of BPA pollution in the surrounding environments. Graphical Abstract Production of raw plastic is the dominant cause of BPA pollution in the environment

The potential application of commercial coffee as a source of electron donors for detoxifying hexavalent chromium [Cr(VI)]-contaminated water was investigated. Various amounts of coffee were reacted with 50 mg/L of artificially prepared Cr(VI)-contaminated water, and the Cr(VI) concentration was monitored as a function of the reaction time using the diphenylcarbazide colorimetric method with an Aquamate 8000 UV-Vis spectrophotometer at a 540-nm wavelength. When the ratio of the coffee mass applied to the volume of Cr(VI) solution was 75 g/L, more than 80% of the initial Cr(VI) disappeared within 5 min of reaction time, and the Cr(VI) concentration became lower than the detection limit of 1 mg/L within 20 min. More Cr(VI) disappeared as more coffee was introduced. In general, smaller particles of coffee were more effective at Cr(VI) reduction, but the advantage that particle size conferred disappeared once the coffee particle size was smaller than 125 μm. As a result, the reduction of the Cr(VI) in the solution was not considered to result from the surface catalytic reduction but by the electron transfer from the electron donors released from the applied coffee.

The study investigated wastewater treatment in an aerobic reactor with activated sludge exposed to static magnetic field (SMF) with mean induction of 8.1 mT. The efficiency of chemical oxygen demand removal was about 90% in a control reactor and an SMF-exposed reactor. Although the nitrification efficiency was higher than 95% in both reactors, the activity of ammonia-oxidizing bacteria was higher in the SMF-exposed reactor. This resulted in shortening of nitrification time to 4 h compared to 8 h in the control reactor. Higher number of ammonia-oxidizing bacteria in the SMF-exposed reactor might result from increased oxygen penetration into the liquid exposed to SMF, which favored growth of these bacteria. The results indicate that SMF enhanced nitrification, the most sensitive process from the biological nitrogen transformations. SMF influenced the overall biomass content that was 14% higher in the SMF-exposed reactor than in the control reactor.

Stopped-flow technology and HPLC analysis were used to study the degradation mechanism and reaction kinetics of 4-chlorophenol (4-CP) in Fenton oxidation process. The results indicated that benzoquinone and hydroquinone were simultaneously produced in process of Fenton oxidizing 4-CP by stopped-flow technology analysis. The data obtained by HPLC showed that hydroquinone was generated in great quantities following the decrease of benzoquinone. It could be inferred by batch experiments that benzoquinone would be transformed into hydroquinone in Fenton process and hydroperoxyl radical (HO₂·) would take the main part in this process. In our study, there would exist two catalytic systems in Fenton process, and one was Fe²⁺and Fe³⁺, the other was hydroquinone and benzoquinone. Moreover, the rate constants of hydroquinone, benzoquinone, and 4-chlorocatechol were 2.78 × 10⁶ L s⁻¹ mol⁻¹, 9.38 × 10⁸ L s⁻¹ mol⁻¹, and 6.47 × 10⁶ L s⁻¹ mol⁻¹, respectively. Graphical Abstract

In this work, we examined the effect of two different organic wastes, composted sheep manure and coir, on the sorption, persistence, and mobility of three pesticides (alachlor, chlorfenvinphos, and chlorpyrifos) included as priority substances in European Directive 2013/39/EU. With this aim, leaching studies were conducted using disturbed soil columns filled with a typical agricultural soil (hipercalcic calcisol) from a semiarid area (southeastern Spain) to determine their potential for groundwater pollution. The three compounds were found in leachates of unamended soil although in different proportions: 53% (alachlor), 9% (chlorfenvinphos), and 6% (chlorpiryfos). The addition of organic wastes significantly increased the sorption of the studied pesticides. As a consequence, the half-lives of the studied pesticides were higher in amended than in unamended soils. A marked reduction of the amount recovered in leachates was observed in the amended soils, except for chlorpiryfos, whose recoveries barely changed. According to their potential groundwater pollution calculated as the groundwater ubiquity score (GUS) index, alachlor and chlorfenvinphos show medium leachability while chlorpiryfos is unlikely to leach.

In this study, cassava starch wastewater was subjected to coagulation/flocculation (C/F) combined with microfiltration (MF) to improve the final quality of treated water. In the C/F tests of the effluent, the best concentration of the natural coagulant (Tanfloc POP) was determined from a statistical analysis of color removal and turbidity data. The supernatant produced in the C/F step was subjected to MF while varying the transmembrane pressure to evaluate the permeate fluxes, fouling mechanism, and permeate quality. The mathematical model that best represented the filtration process was the fouling mechanism of partial membrane pore blockage. The best experimental conditions for coagulant dosage, settling time, and MF pressure in the combined C/F-MF process were 320 mg L⁻¹, 15 min, and 1.4 bar, respectively. The highest overall removal efficiency rates achieved were 99% color, 91% cyanide, 75% total organic carbon, and 100% turbidity, demonstrating the promising potential of the combined C/F-MF process in the treatment of cassava starch wastewater.

This study was conducted to determine the optimal conditions for PAH degradation from highly contaminated attrition sludge (PAC) using a Fenton process or successive permanganate (KMnO₄) oxidation and Fenton processes. The following parameters were studied to optimize the Fenton oxidation process: the amounts of reactants based on the stoichiometric oxidant demand (SOD), the reactant addition protocol and number of doses, and the solid/liquid ratio (S/L). The results showed that the following conditions were optimum: TS = 30%, 7.5 times SOD, H₂O₂/Fe²⁺ ratio = 10, and added five times during 60 min, which allowed the degradation of 43% of total 27 PAHs from the PAC. Successive Fenton and KMnO₄ oxidation processes were also tested. PAH degradation using a sequential Fenton process followed by KMnO₄ oxidation (or KMnO₄ followed by Fenton) was higher than for the use of Fenton or KMnO₄ treatment alone. Up to 71% of the total 27 PAHs were degraded when using a combination of both processes. It appeared that the sequential treatment is a viable method for the significant degradation of 27 PAHs from PAC (t value > 2.77).

With an annual production of about 10 Gt concrete is by far the most used solid man-made material. In order to adjust the workability of fresh concrete most often so-called superplasticisers, essentially water-soluble organic polymers, are utilised. As concrete is commonly in direct contact with soil or water, the leaching of organic and inorganic compounds and their environmental impact need to be assessed. The present study contributes to this purpose by investigating leachates from hardened cement pastes gained using the horizontal dynamic surface leaching test. Pastes were prepared with and without superplasticiser. The root growths as well as the germination behaviour of cress (Lepidium sativum) and white mustard (Sinapis alba) were examined with respect to phytotoxicity. Different proportions (100, 50, 25 and 12.5%) of the leachates were considered in the test scheme. The results indicate a positive effect of most of the leachates on seed germination and root growth, although statistical significance was only found in some cases. Both test species showed no or only slight harmful effects as relative root growth exceeded always 66% for S. alba and 74% for L. sativum. Seed germination was not negatively influenced by the leachates. Slight beneficial effects on both test species could be observed for leachates containing superplasticiser compared to samples in absence of superplasticiser.